I was at the same seminar and I can promise you that Jay and Mike did not suggest cutting from the back.
A lot of the UK compound shooters at the time were recommending cutting 1" or more off the back (Peart/White etc) - which is probably were the confusion came from - I'd guess that probably still stands. Also at the time the majority of the top UK target recurve shooters were shooting ACEs out of preference and I heard a lot of them talking about cutting from the back X10s but would you take advice from someone who's choosing to shoot something else
However, off the recurve it is just a waste (unless you buy a spine weak by mistake and need to stiffen then). I've shot 410 or 450 since 1997 and as long as I get the right spine I've always been happy chopping the whole lot off the front
HTH
Stretch